Spring balance assembly

Abstract

The present invention provides a balance assembly for use with a sash window assembly slidable within a master frame. The balance assembly generally includes a plate, a spring assembly, and a brake shoe or pivot brake assembly. The plate is removably connected to the master frame. The spring assembly includes a first spring that is inter-wound or nested within a second spring. Each spring has a coiled portion, an intermediate portion, and a free portion. The coiled portions of the springs are rotatably supported by the support member that extends from the plate. The free portions of the springs have a curved configuration and are received by a slot in the brake shoe, which is operably coupled to the sash window. The inter-wound springs exert a balancing force on the sash window during movement of the window.

1 . A balance assembly for a sash window slidable within a master frame, the balance assembly comprising: 
 a holder adapted to be connected to the master frame;    a first coil spring operably connected to the holder, the first coil spring having a coiled portion and a free end portion;    a second coil spring having a coiled portion and a free end, wherein the second coil spring is nested within the first coil spring, and wherein both free end portions are adapted to be connected to the sash window.    
   
   
       2 . The balance assembly of  claim 1 , wherein the holder has a support member extending from the plate to rotatably support the first and second springs.  
   
   
       3 . The balance assembly of  claim 2 , wherein the support member rotatably engages an outer surface of one of the first spring and the second spring.  
   
   
       4 . The balance assembly of  claim 1 , wherein the coiled portion of the first spring is positioned adjacent to the coiled portion of the second spring.  
   
   
       5 . The balance assembly of  claim 1 , wherein the free end portion of the first spring is positioned adjacent to the free end portion of the second spring.  
   
   
       6 . The balance assembly of  claim 1  further comprising a brake shoe configured to be operably connected to the sash window, wherein the free portions of both springs are coupled to the brake shoe.  
   
   
       7 . The balance assembly of  claim 1 , wherein the free end of each spring has a curvilinear configuration.  
   
   
       8 . The balance assembly of  claim 6 , wherein the free end of each spring has a curvilinear configuration and both free ends are received by a curvilinear slot in the brake shoe.  
   
   
       9 . A balance assembly for a sash window slidable within a master frame, the balance assembly comprising: 
 a plate adapted to be connected to the master frame;    a first coil spring operably connected to the plate, the first coil spring having a coiled portion;    a second coil spring having a coiled portion, wherein the second spring is inter-wound with the first spring; and,    a shoe connected to the inter-wound first and second springs.    
   
   
       10 . The balance assembly of  claim 9 , wherein the plate has a support member extending from the plate to rotatably support the first and second springs.  
   
   
       11 . The balance assembly of  claim 9 , wherein the first and second coil springs each have a curvilinear free end.  
   
   
       12 . The balance assembly of  claim 11 , wherein the shoe has at least one slot that receives the curvilinear free end of both springs.  
   
   
       13 . The balance assembly of  claim 12 , wherein the slot has a protrusion that engages and secures the free ends within the slot.  
   
   
       14 . The balance assembly of  claim 9 , wherein the coiled portion of the first spring is positioned adjacent to the coiled portion of the second spring during operation of the balance assembly.  
   
   
       15 . The balance assembly of  claim 9 , wherein the free portion of the first spring is positioned adjacent to the free portion of the second spring during operation of the balance assembly.  
   
   
       16 . The balance assembly of  claim 8  wherein the first coil spring has a width, and the second coil spring has a width that is different from the width of the first coil spring.  
   
   
       17 . A balance assembly for a sash window slidable within a master frame, the sash window being operably connected to a brake shoe having a curvilinear slot, the balance assembly comprising: 
 a spring assembly adapted to be connected to the master frame, the spring assembly having a first coil spring with a coiled portion and a curvilinear free end, the spring assembly further having a second coil spring with a coiled portion and a free end, wherein the second spring is inter-wound with the first spring, and wherein the curvilinear free end of the first spring is configured to be received by the curvilinear slot.    
   
   
       18 . The balance assembly of  claim 17 , wherein the second springs has a curvilinear free end.  
   
   
       19 . The balance assembly of  claim 18 , wherein the curvilinear free end of the second spring is configured to be received by the curvilinear slot.  
   
   
       20 . The balance assembly of  claim 17 , wherein a free end of the second spring is connected to the first spring near the free end of the first spring.  
   
   
       21 . A balance assembly for a sash window slidable within a master frame, the balance assembly comprising: 
 a plate adapted to be connected to the master frame;    a first coil spring operably connected to the plate, the first spring having a coiled portion and a curvilinear free end;    a second coil spring having a coiled portion and a curvilinear free end, wherein the second coil spring is inter-wound with the first coil spring; and,    a brake shoe having a pair of slots, wherein each slot receives a free end of the inter-wound first and second springs.    
   
   
       22 . The balance assembly of  claim 21  wherein the plate has a support member extending from the plate, wherein the support member rotatably engages one of the first and second springs.  
   
   
       23 . The balance assembly of  claim 21  wherein each slot has a curvilinear configuration and is cooperatively dimensioned with the free end of the springs.  
   
   
       24 . The balance assembly of  claim 21  wherein the coiled portion of the first spring is positioned adjacent to the coiled portion of the second spring.  
   
   
       25 . The balance assembly of  claim 24  wherein each coiled portion has a terminal end, and wherein the terminal end of the first spring is positioned adjacent to the terminal end of the second spring.